The present invention relates to a plasma processing apparatus and a plasma processing method, and in particular to a plasma processing method of conducting a matching operation with respect to a radio frequency (RF) power supply having periodical repetition of a high output period and a low output period.
In recent years, further high precision of working has been demanded in etching processing using plasma with the progress of miniaturization and integration of semiconductor devices. As a solution for such a problem, it has been known from the past that selectivity of a film of a processing target formed in advance on a top surface of a sample can be improved by changing with lapse of time (temporally), the magnitude or frequency of RF power applied to a sample or electrodes within a sample stage which holds the sample, in order to form bias potential over the sample, or changing power which forms an electric field supplied to form plasma, i.e., conducting the so-called modulation, during processing of the sample of the etching processing target.
Furthermore, it has been known that the amount of deposits which adhere to an inner wall of a processing chamber within a vacuum vessel where plasma is formed and processing on a sample is performed, during processing of the sample, or peeling off of the deposits can be reduced, by periodically repeating increase or decrease of the magnitude (amplitude) of RF power for forming a bias. For example, it has been known to conduct etching by conducting amplitude modulation on RF power for forming bias potential during etching processing with repetition of a high output period and a low output period
As such related art, a technique disclosed in JP-A-2013-012624 is known. JP-A-2013-012624 discloses a plasma processing apparatus or a plasma processing method that facilitates control and cleaning of dust particles by using RF power for forming bias potential having periodical repetition of a high output period and a low output period and thereby causing a quality of material of a film deposited on a surface of a working shape such as grooves and holes of the film of the processing target during processing to become amorphous.